Cardiac output and measurement of cardiac dimensions and haemodynamics are very important indicators in measuring health or detecting disease. The cardiac output, the volume of blood ejected by the heart per minute, is an essential measure of cardiac health.
Unfortunately, it is often difficult to measure actual cardiac output. Whilst normal fluid flow outputs consist of a flow velocity times a cross section area, it is often difficult to accurately measure the cross sectional area of cardiac vessels. Hence, there is often a large degree of error associated with actual cardiac measurements.
This is particularly the case with small pre-term infants and, even, foetuses. It would be desirable to be able to measure the cardiac output of such individuals.